Different mobile network operators may have different network design objectives that they wish to meet through either the centralisation or the distribution of RAN functions. For example:                locating radio link cryptographic operations in a central data centre allows encryption used over a radio link to be exploited to also provide secrecy over a backhaul network. This may obviate the need for secondary encryption mechanisms in the backhaul network and eliminate the need for separate security gateways, thus reducing network deployments costs.        locating user traffic processing operations close to a cell site enables forwarding of data to local Internet gateways and to mobile edge computing functions. This may provide lower latency and/or lower backhaul costs.        locating all cryptographic functions in a central data centre may enhance network security and reduce the requirements for secured cell sites.        locating non-real time control plane functions in central data centre may enable use of network function virtualisation for these functions which may lower costs and provide greater scalability.        
A wireless user device may initiate one or more data sessions where different data sessions may have different service requirements. The user plane entities responsible for different sessions may need to be instantiated in different locations within the public land mobile network (PLMN) in order to meet the service requirements of their associated session. Similarly, control plane entities for different wireless user devices or for different sessions may be instantiated in locations within the RAN that are different from the locations chosen for user plane entities.
In addition, user plane entities responsible for uplink traffic may be instantiated in locations different from user plane entities responsible for downlink traffic. For example, user plane uplink traffic entities may be located close to a cell site for connection to local Internet gateways while user plane downlink traffic entities may be located centrally, close to a mobility anchor point.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.